Wednesday, September 29, 2010

First international DX in FM on 2-Meters tonight!

Flying high right now, as I was able to hit over 110 miles on 2 meters, using only 20 watts power in FM mode. My longest contacts yet on 2m FM. I was scanning my Yaesu FT-8900R on the way to the store tonight, and picked up a weak repeater signal on 147.32 Mhz. I rolled to a stop after finding a spot with a peak signal strength of an S-4 reading, contacted and was able to chat with two blokes in Burnaby and New Westminster, British Columbia from Renton, WA.

Turns out the repeater I was hitting and bouncing off of at 20w is:
VE7RSI
Salt Spring Island Amateur Radio Club
SALT SPRING ISLAND, BC V8K 2H8
Canada

Distance between Maidenhead Grid Squares:
CN87vk to CN88fv: 117.9 Miles

My longest distance before was in the Cascade Mountains, on a Simplex frequency a couple of years ago:
CN97ej to CN87kf: 70 Miles

"Big Deal, it's only a repeater on 2 meters in FM...not impressed"

So what? I don't even have an HF rig yet, I can't hit thousands of miles in CW or SSB on QRP (less than 5 watts). For me tonight, it's an accomplishment to make my first International DX, still being wet-behind-the-ears in HAM radio, in any mode...and still able to do it under the max power or my mobile VHF rig (50 watts).

73's!

Tuesday, September 28, 2010

DIY Stompboxes - Matsumin's ValveCaster

Here is a simple Tube Overdrive/Boost pedal that can be built in a weekend if you have enough materials laying around (or if you spent some time & money and sourced the materials commercially).

It is based on Matsumin's ValveCaster, which has plans and a discussion thread a mile long on DIYStompboxes.com. Unlike Tube Amplifiers, this is a simple 9-12 Volt circuit, and can be built for under $50 (not including tube). It sounds incredible between a guitar and both tube or solid-state amplifier. It is versatile enough design that you can incorporate other effects into the same pedal, or go beyond for more stages. Take a listen to one of these builds, courtesy Dovinia:


(I would post a video of my own, but I am still a n00b at playing the guitar. I have had more fun building this stuff, and watching the reactions of regular players who get a feel of the tone of this thing with their own playing.)

Here are a couple of more links with others builds of the same design:
Some sweet licks and tone on a one single tube
Not enough? Go for two stages of gain!
Or even more...here are 3 chained together

With enough love and care in the manufacturing process, you could have a world-class tube overdrive pedal that is completely unique in design, and sounds just as good as one of the expensive boutique tube-overdrive pedals out there. Here is what I created and painted in my garage last winter which I hope to post videos of soon:



The name just stuck...It's a 12AU7 tube pedal running with a starved plate (cold) at 9-12 volts, while the 12AU7's specifications are designed to operate at over 200 volts in an amp.

Monday, September 27, 2010

Video of the day - Journey to the Center of a Tube



These guys at TubeDepotTV are the best, good video productions and very educational. Also they fully stock components at tubedepot.com for building and repairing amplifiers.

This video, available in 1080p is a very detailed and accurate description of how tubes are constructed, and how they work. Enjoy :)

PUBLIC SERVICE ANNOUNCEMENT

A WORD ABOUT HIGH-VOLTAGE SAFETY
Many people don't know that working in tube amps can be extremely dangerous. There are LETHAL voltages inside these things when they are powered up, and for a time after they are powered down, even days. It is entirely up to you if you wish to risk your life working inside one of these, otherwise refer to a qualified and experienced Amp technician.

This is not a hobby for the faint of heart, but if you commit a few safety rules to memory, then you will live a long healthy life without getting electrocuted or bitten by a nasty jolt due to carelessness:

* ALWAYS WORK ONE-HANDED whenever working inside an amplifier or other tube-based electronics. This does not matter if it is powered up or not. The Capacitors can hold a charge for a long time, unless discharged properly. Once you can confirm that your Volt-Ohm-Meter measures 0 Volts DC from the B+ to Ground, then it is safe to work with both hands after unplugging. Otherwise, shove your non-dominant hand into your back pocket, and leave it there.

* NEVER WORK TWO-HANDED if you are not sure if your amp still has a charge. Since if you make a circuit between your hands, the current will flow straight across your heart. I can't reiterate this point enough.

* OBSERVE PROPER POLARITIES of components, otherwise you risk fires or or exploding capacitors in your hardware...And you will weep if you destroy an expensive piece of Iron (transformers) or pop expensive tubes.

* CAREFULLY CALCULATE YOUR MOVES AND ACTIONS before attempting to probe a hot circuit. Don't be careless. Use an insulated probe like a glass rod, fiberglass rod or dry wooden chopstick.

* A "BLEEDER RESISTOR" CAN SAVE YOUR LIFE. This is simply a 100KΩ 1-watt resistor attached to the High-Voltage B+ rail at the first stage (the Plate of Tube 'V1'), and grounded to the input jack's ground. After you power down your amp and unplug it, this will slowly bleed all the remaining current from the capacitors, typically over a period of 2-10 minutes. Confirm afterward by measuring the B+ rail to ground that you get 0 Volts DC before attempting to work inside of it.

(In progress, stay tuned for updates to this post)

Site of the week - AX84.com

http://AX84.com
This place is AWESOME for the DIY Guitar Amplifier builder.
------------

The first amp I built was the AX84 P1 starter project in the Spring of 2008, in my roommate's garage, and was actually brought to tears when I heard that sweet, sweet tone coming from it for the first time.



The second amp I built, the AX84 October Club, has been more challenging, and happened during the winter of 2008-2009 in the basement of the house I was living at with my brother. It is not quite finished yet, but I have a good idea of what I components I need to remove from it, to put it in full working order.

Now just to find the time to do it!

DIY Steadicam - on Metalworking and Movies


Here is the pic as promised of the tennis racket that I sliced up with my camcorder next to it, so you can get an idea of how far along I am in this project.

Next I need to source/fabricate the following:

* usable gimble to attach to a handle. Wsclater's site had some recommendations that I will check out.
* Metal plates to fasten to the boom and camera
* Washers and bolts to serve as weights & counter-weights

Probably more is needed, but still need to do more planning and study

Saturday, September 25, 2010

Building Guitar Amplifiers - Chapter 1 - "One man's junk is another man's treasure"

In late 2005, I had been doing some extended house-sitting at my Grandpa's place on the Kitsap Peninsula before he passed away. Unfortunately, the house was also populated by 50-years worth of "junk" that Grandpa never threw away. I mean this...Grandpa never threw ANYTHING away, as it was probably some wisdom and result from growing up in the Great Depression. The monumental task of the Estate cleanup left to our family. Growing up, I had always imagined that Grandparents houses always had some hidden treasure socked away somewhere. This was piqued when Grandpa had once told me earlier that "there's a lot of good stuff in there"...

As my family was cleaning out the upper rooms and basement my mom walked in to my bedroom holding a curious glass bulb. She asked "What's this going for on eBay?" Looking it over, I could see that it was very old and manufactured by Raytheon. That's funny, I always imagined them as a Defense Contractor...but in Western Washington we have a lot of those, along with a lot of Military installations, and Aerospace (Boeing).

I looked up the identifier on this 60-70 year old tube, and could not believe what showed up on eBay. This tube was regularly being bought in some fierce bidding wars for around $75 a piece. What are these things??

Mom took me down to the basement and proceeded to tell the story of her Dad, and how he worked as an Electrician at the Bremerton Naval Shipyards in the 1940's and then later opened up a TV-Radio repair shop in North Seattle. After Grandpa's shop had closed up when he retired, he took all his old stock and socked it away in his basement, along with literally tons of old and broken TV's (at least 50 of them).

Unfortunately a lot of the good NOS components (tube sockets, resistors, capacitors) had already made it to the dumpster because no one knew if this stuff had any value. But none of the old vacuum tubes had been thrown away. She told me that since no one else had claimed any of the remaining electronics, I was free to take what I desired.

A treasure hunt had begun! I scoured the basement and found boxes of tubes, and more boxes, and drawers and more boxes, and all the old 50's-60's era TVs, and more boxes filled with new and used tubes that had been collecting dust for half-a-century. I ended up with approximately 1500 tubes initially, some nice vintage resistors (carbon-composition) and vintage sealed capacitors (paper-in-oil) that were spared from the dumpster.

I eventually took most of the next spring and summer going through and cleaning out the basement of all the old TV's by destroying and trashing all the old moldy cases and separating out the CRT's which required recycling. The prize of each old TV one was the electrical chassis which contained all the components like tube sockets, resistors, capacitors, coils, cloth wire, even solder.

What would I do with all of this? About 10 years prior, I had followed a buddy of mine into Speedster Amplifiers in Gig Harbor, WA, and seen their operation. And this memory inspired me to want to build Guitar Amplifiers or even Hi-Fi amplifiers if I wanted.

Washington is full of environmental hippies, so the axiom "Reduce, Reuse, Recycle" was everywhere. Why couldn't I do my part and spare the landfills of some toxic materials that didn't need to be there in the first place? With a Dremel in hand, I started cutting out and testing components of all the old chassis so I could reuse them for newly-manufactured amplifiers.

To be continued...

DIY Steadicam - How to end hand-jerk in your videos on a budget

As you can see from my demonstration video below, hand-jerk when using a handheld camera is a problem for many people.

I am working on building a DIY Camera Stablizer (commercially known as a Steadicam). Here is one Scotsman, Wsclater, with his implementation and some working designs on his website. This gentleman's demonstration is what inspired me to get started on my own.


His rig in action:


Search YouTube for "DIY Steadicam" and you will find some working examples of other people's work. But so far finding a sufficient curved boom to mount the camera and counter-weights has been a challenge, but I have found tonight that using a chopped up Aluminum tennis racket frame may do the trick as it is already pre-drilled, rigid and should be easy to adjust. (Will post a picture of tonight's cuts after finding a camera)

Video test



Testing out an HD Camcorder, watch full screen in full resolution. It may take a few minutes for 720p and higher to be enabled.

First Post (ie. Rantings and Ravings from a Jaded Tech)

Getting all of this set up and working on posting some video of some current and not-so-current projects from a 30-something who has been involved in computers since the days of the Commodore VIC-20...

Stuff like:
* Amateur Radio (HAM Radio)
* Music and Music Production (Software, Hardware and Instruments),
* Vintage stuff like Vacuum Tubes (and what you can do with such obsolete technology, like building Guitar Amplifiers)
* Videos and other media are coming soon, including an instructional on building your Guitar Amp from scratch, even in HD goodness!

It will be a big mix of old and new, modern and vintage...much like my 30's so far